The prior art processes of forming a fat continuous product involved the mixing of an aqueous and a fat phase at room temperature (greater than 30.degree. C.) or above and then cooling the formed emulsion in one or more scrapped surface heat exchanger units (A-units) to cool the emulsion and start the crystallization process by removing the heat of crystallization. The cooled emulsion then passes from the A-unit into one or more C-units where crystallization continues to substantially form beta prime fat crystals of the product. Depending on the desirable residence time additional C-units and B-units may be added to the production line the typical residence time for fat continuous products having a trans fatty acid level of greater than about 10% is 30 seconds to 5 minutes.
Lately, consumer trends have been towards spread products which spread easily, have a good melting behavior in both the mouth and on heated food items, contain a relatively high proportion of unsaturated fatty acids and at the same time have a relatively low trans fatty acid level, preferably lower than 10%. In general butter has a trans fatty acid content of about 7 to 8%.
The higher the level of trans fatty acid in the fat phase of a spread, the shorter the residence time needed during processing to crystallize the fat to form the desirable characteristics of the spread. As the trans fatty acid content is reduced, residence times must be increased in order to avoid post crystallization of the fat during storage which leads to brittle and unspreadable products. Adding additional units to the production line increases cost and removes flexibility of modifying the process line configuration.
There therefore exists a need for a process to prepare a spread having less than 80% fat and less than 10% trans fatty acid levels, which has exceptable consumer properties such as good spreading and good organoleptic characteristics.
Another object of the invention is to provide an improved process for forming fat continuous products which is both economical and yet flexible enough to be modified to achieve desirable residence time in line in processing fat spreads with varying levels of trans content.